A contemporary vision of raw earth architecture

The renewed attention paid to raw earth construction in recent decades is linked to its undoubted sustainability, cost-effectiveness, and low embodied energy. In Italy, the use of raw earth as a construction material is limited by the lack of a technical reference standard and is penalised by the current energy legislation for its massive behaviour. Research experiences, especially transoceanic, on highly performative contemporary buildings made with natural materials show that raw earth can be used, together with different types of reinforcements, to create safe, earthquake-resistant, and thermally efficient buildings. On the basis of experimental data of an innovative fibre-reinforced rammed earth material, energy analyses are developed on a rammed earth building designed for a Mediterranean climate. The paper focuses on the influences that different design solutions, inspired by traditional bioclimatic strategies, and various optimised wall constructions have in the improvement of the energy performance of the abovementioned building. These considerations are furthermore compared with different design criteria aiming at minimising embodied carbon in base material choice, costs, and discomfort hours. Results have shown the effectiveness of using the combination of massive rammed earth walls, night cross ventilation, and overhangs for the reduction of energy demand for space cooling and the improvement of wellbeing. Finally, the parametric analysis of thermal insulation has highlighted the economic, environmental, and thermophysical optimal solutions for the rammed earth envelope.

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Clay-Based Products Sustainable Development: Some Applications

Sustainability ◽

10.3390/su13031364 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1364

Author(s):

Michele La Noce ◽

Alessandro Lo Faro ◽

Gaetano Sciuto

Keyword(s):

Sustainable Development ◽

Tensile Strength ◽

Compressive Strength ◽

Elastic Modulus ◽

Basalt Fibers ◽

Future Studies ◽

Clay Bricks ◽

Brick Powder ◽

Alkaline Resistance ◽

Raw Earth

Clay has a low environmental impact and can develop into many different products. The research presents two different case studies. In the first, the clay is the binder of raw earth doughs in order to produce clay-bricks. We investigate the effects of natural fibrous reinforcements (rice straws and basalt fibers) in four different mixtures. From the comparison with a mix without reinforcements, it is possible to affirm that the 0.40% of basalt fibers reduce the shrinkage by about 25% and increase the compressive strength by about 30%. Future studies will focus on identifying the fibrous effects on tensile strength and elastic modulus, as well as the optimal percentage of fibers. In the second study, the clay, in form of brick powder (“cocciopesto”), gives high alkaline resistance and breathability performance, as well as rendering and color to the plaster. The latter does not have artificial additives. The plaster respects the cultural instance of the original building. The research underlines how the use of a local (and traditional) material such as clay can be a promoter of sustainability in the contemporary building sector. Future studies must investigate further possible uses of clay as well as a proper regulatory framework.

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Raw earth construction: Is there a role for unsaturated soil mechanics?

Unsaturated Soils: Research & Applications ◽

10.1201/b17034-8 ◽

2014 ◽

pp. 55-62 ◽

Cited By ~ 5

Author(s):

D Gallipoli ◽

A Bruno ◽

C Perlot ◽

N Salmon

Keyword(s):

Unsaturated Soil ◽

Soil Mechanics ◽

Earth Construction ◽

Unsaturated Soil Mechanics ◽

Raw Earth

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Fire Behavior of Raw Earth Bricks: Influence of Water Content and Cement Stabilization

10.4028/www.scientific.net/cta.1.792 ◽

2022 ◽

Author(s):

Rafik Isaam Abdallah ◽

Céline Perlot ◽

Hélène Carré ◽

Christian La Borderie ◽

Haissam El Ghoche

Keyword(s):

Water Content ◽

Thermal Instability ◽

Fire Behavior ◽

Standard Fire ◽

Influence Of Water ◽

Cement Stabilization ◽

The One ◽

Raw Earth ◽

Water Contents ◽

Soil And Water

This study focus on the effects of both water content and cement stabilization on the fire behavior of earth bricks. To observe the effect of cement stabilization, two materials are formulated: raw earth with only soil and water, and stabilized bricks with soil, water and cement (3.5% by mass of soil). Since the material’s mechanical strength can strongly influence its fire behavior, the raw bricks were compacted at 50 MPa to reach a compressive strength similar to the one of stabilized bricks. Four different water contents were tested; dry state obtained with oven drying and three others achieved through equalization at 50%, 75% and 100% of relative humidities. Bricks are then subjected to an ISO 834-1 standard fire. Results show that water content has caused a thermal instability behavior on the raw earth bricks after equalization at 50% and 75% relative humidities. Thermally stable bricks displayed a noticeable diffusion of cracks on their heated face. Furthermore, cement stabilization helps to prevent from thermal instabilities.

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Effect of adding insulation on the energy performances of rammed earth buildings in hot and arid climates

E3S Web of Conferences ◽

10.1051/e3sconf/202015001011 ◽

2020 ◽

Vol 150 ◽

pp. 01011

Author(s):

Wical Cheikhi ◽

Khadija Baba ◽

Abderrahman Nounah ◽

Choukri Cherradi

Keyword(s):

Good Alternative ◽

Energy Performance ◽

Simulation Software ◽

Sustainable Construction ◽

Rammed Earth ◽

Before And After ◽

Energy Consuming ◽

High Level ◽

Earth Walls ◽

Raw Earth

In a world context focused on energy efficiency and sustainable construction, returning to the use of raw earth in construction constitutes a good alternative to concrete construction, a system more energy consuming and yet more used nowadays. This return is justified by the excellent energy performance and the high level of thermal comfort provided by earth constructions in different climates. In cold climates, adding an insulation on earth walls has proven to be effective in improving their thermal performances. However, the influence of adding an insulation on the energy performance of rammed earth buildings in hot and arid climates remains to this day little explored. The present work comes in this order of ideas; it is based on a comparative study of the energetic performances of a mud building before and after the addition of the insulation. In order to compare between their performances, we have performed a simulation of the thermal behaviour of each by the dynamic thermal simulation software Design Builder.

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Mechanical and thermophysical properties of raw earth bricks incorporating date palm waste

Construction and Building Materials ◽

10.1016/j.conbuildmat.2020.121824 ◽

2021 ◽

Vol 270 ◽

pp. 121824

Author(s):

Daifallah Khoudja ◽

Bachir Taallah ◽

Ouarda Izemmouren ◽

Salima Aggoun ◽

Ouided Herihiri ◽

...

Keyword(s):

Thermophysical Properties ◽

Date Palm ◽

Date Palm Waste ◽

Raw Earth ◽

Palm Waste

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Risk of damage and desiccation cracking of construction materials based on raw earth

MATEC Web of Conferences ◽

10.1051/matecconf/201928101018 ◽

2019 ◽

Vol 281 ◽

pp. 01018 ◽

Cited By ~ 1

Author(s):

Ahmad El Hajjar ◽

Joanna Eid ◽

Tariq Ouahbi ◽

Said Taibi

Keyword(s):

Digital Image Correlation ◽

Construction Materials ◽

Image Correlation ◽

Correlation Technique ◽

Digital Image Correlation Technique ◽

Initiation And Propagation ◽

Desiccation Cracking ◽

Natural Aggregates ◽

Raw Earth ◽

Homogeneous Strain

Nowadays, structures are mainly constructed using natural aggregates as sand and gravels. In the future, we would increasingly have to consider replacing them by more abundant and ecological natural materials such as raw earth. However, despite its many qualities (low gray energy, thermal and hygrometric isolation), this eco-material has some defects: cracking by desiccation. The later prevent its widespread diffusion. This study aims to understand the mechanisms of appearance and propagation of cracks in order to try to either prevent or repair it. To carry out this study, digital image correlation technique is used. It consists in performing free desiccation tests to follow the initiation and propagation of cracks, from the beginning of homogeneous strain until the appearance of discontinuity, in order to determine the strains tensor in the massif. In order to understand the origin of cracking, desiccation is studied for different boundary conditions and according to different intrinsic characteristics of the material.

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Estimation of EOP from VLBI: Direct Approach

International Astronomical Union Colloquium ◽

10.1017/s0252921100000373 ◽

2000 ◽

Vol 180 ◽

pp. 254-258 ◽

Cited By ~ 1

Author(s):

L. Petrov

Keyword(s):

Time Series ◽

Harmonic Component ◽

Segment Length ◽

Physical Parameters ◽

Earth Orientation Parameters ◽

Earth Orientation ◽

Alternative Approach ◽

Two Stages ◽

Orientation Parameters ◽

Raw Earth

AbstractThe currently adopted strategy of EOP estimation from VLBI is to estimate six parameters: UT1, UT1 rate, pole positions and nutation offsets for each 24-hour session independently. Then the resulting time series of raw Earth orientation parameters are filtered and a regression analysis is performed in order to obtain nutation coefficients, polhode of the pole and other physical parameters. Thus, the latter parameters are obtained indirectly in two stages. An alternative approach of direct estimation of the final Earth orientation parameters is presented. Pole coordinates and UT1 are considered as a sum of three components: the low-period component which is modeled by a cubic spline, the harmonic component which includes forced nutation, precession and sub-daily variations of EOP, and the stochastic component which is modeled by a linear spline with segment length 1-2 hours. All parameters are obtained in a single LSQ solution using all available data.

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